Some of these problems can also occur if you have a deficiency in vitamin B12 or folate, but don't have anaemia.

When to see your GP

See your GP if you think you may have a vitamin B12 or folate deficiency. These conditions can often be diagnosed based on your symptoms and the results of a blood test.

It's important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms improve with treatment, some problems caused by the condition can be irreversible.

Causes of a vitamin B12 or folate deficiency

There are a number of problems that can lead to a vitamin B12 or folate deficiency, including:

pernicious anaemia – where your immune system attacks healthy cells in your stomach, preventing your body from absorbing vitamin B12 from the food you eat; this is the most common cause of vitamin B12 deficiency in the UK

a lack of these vitamins in your diet – this is uncommon, but can occur if you have a vegan diet, follow a fad diet or have a generally poor diet for a long time

medication – certain medications, including anticonvulsants and proton pump inhibitors (PPIs), can affect how much of these vitamins your body absorbs

Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people aged 75 or over, and 1 in 20 people aged 65 to 74.

Treating vitamin B12 or folate deficiency anaemia

Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the missing vitamins.

Vitamin B12 supplements are usually given by injection at first. Then, depending on whether your B12 deficiency is related to your diet, you'll either require B12 tablets between meals or regular injections. These treatments may be needed for the rest of your life.

Folic acid tablets are used to restore folate levels. These usually need to be taken for four months.

In some cases, improving your diet can help treat the condition and prevent it recurring. Vitamin B12 is found in meat, fish, eggs, dairy products, yeast extract (such as Marmite) and specially fortified foods. The best sources of folate include green vegetables such as broccoli, Brussels sprouts and peas.

Complications of vitamin B12 or folate deficiency anaemia

Although it's uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you've been deficient in vitamin B12 or folate for some time.